[REGRESSION] drm/amd/display: backlight brightness set to 0 at amdgpu initialization

[Mario Limonciello]

On 7/18/2025 9:36 AM, Lauri Tirkkonen wrote:
> On Fri, Jul 18 2025 08:10:06 -0500, Mario Limonciello wrote:
>> Do you by chance have an OLED panel?  I believe what's going on is that
>> userspace is writing zero or near zero and on OLED panels with older kernels
>> this means non-visible.
> 
> Yes, this is an OLED panel. But I don't believe it's userspace writing
> anything at this point in the boot; before the bisected commit,
> brightness was set to 32 (out of max 255) on this hardware when I
> checked from the initramfs rescue shell. At the bisected commit, it's 0
> (out of max 255).
> 
>> There is another commit that fixes the behavior that is probably missing.
> 
> Which commit is that? It's not in 6.15.7?
> 

https://github.com/torvalds/linux/commit/39d81457ad3417a98ac826161f9ca0e642677661

No; it's not currently backported.  Assuming it helps your issue I think 
it's a good argument to backport.